A variety of check valve means have been incorporated within fuel dispensing nozzles, for many years, and which provide for either the control of the fuel being dispensed, or to regulate the vapors that may be returned back through the nozzle, during their collection, particularly in those devices designed for achieving Stage II type of vapor recovery, in the design and functioning of fuel dispensing nozzles. As is well known, many jurisdictions now require that the discharge of vapors to the atmosphere, during fuel dispensing, as at the service station, be substantially eliminated. Hence, generally, two types of nozzles have been devised, one is the vacuum assist type, wherein a vacuum pump means locates either in the dispenser or in the underground fuel storage tank, or at some other location, which provides for a reduction of pressure and the attraction of vapors back into the nozzle, for return and collection, to prevent their discharge into the atmosphere. Furthermore, the balanced pressure type of vapor recovery, normally of the type that incorporates a bellows means for sealing against the automobile fill pipe that leads to the gasoline tank, provides means for collecting vapors, that are forced back out of the vehicle fuel tank, as gasoline is dispensed therein, with such vapors being returned through a bellows means arranged concentrically upon the nozzle spout, and then returned back through the nozzle to the storage location. Generally, either one of these instruments normally include some type of check valve means, located at some region within the vapor flow path, of the nozzle, for preventing the release of vapors back into the atmosphere, particularly after a nozzle dispensing function has been concluded.
There are a variety of patents that disclose various types of vapor seals, such as when gasoline is being dispensed, in order to prevent its escape, such as shown in the U.S. Pat. No. to Madden, 3,753,453. The U.S. Pat. No. to Burtis, 3,907,010, discloses an anti-pollution service station assembly, wherein a seal is made by means of a vapor member, in the vicinity of a valve, to allow the passage of vapors through various ports, as when gasoline is being dispensed, but to provide for its closure when fuel dispensing ceases. The U.S. Pat. No. to Braun, 3,946,771, shows a type of check valve, which appears to be a type of flapper valve, for curtailing the passage of vapors, when dispensing of fuel has shut-off. The U.S. Pat. No. 4,018,252, also to Burtis, is similar to his previously described patent. This particular device operates off of the poppet stem for the shown nozzle.
The U.S. Pat. No. 4,057,085, shows another form of vapor recovery system, but it locates its recovery means within the dispenser, rather than at the nozzle. U.S. Pat. No. 4,199,012, discloses a vapor recovery arrangement, but obviously the vapors pass through the vapor recovery tube incorporated into the nozzle guard. A patent to Healy, U.S. Pat. No. 4,343,337, upon a fuel dispensing nozzle, shows a poppet valve that apparently provides for sealing of a vapor return line, as through its nozzle, and this vapor return path apparently is sealed by means of a valve seal, operated by the poppet stem.
The patent to Walker, U.S. Pat. No. 4,429,725, discloses a check valve that provides for passage of vapors through and to the vapor recovery conduit. The U.S. Pat. No. 4,825,914, shows another vapor check valve, to curtail the flow of vapors, when the nozzle is withdrawn from a fuel tank. The U.S. Pat. No. to Nitzberg, 4,827,960, shows a vapor control means embodied in a breakaway swivel coupling.
Another U.S. Pat. No. 4,497,350, upon a vapor recovery system, shows an automatic shut-off feature for the nozzle that relates to its opening and closure of a valve, that regulates the flow of liquid, but not vapors, as such passes through the shown nozzle.
The U.S. Pat. No. to Barr, 3,996,979, shows a valve means which is rendered operative by the elevation of a popper stem.
Other United States patents showing various types of mechanisms for automatic nozzles are disclosed in the patent to Moore, U.S. Pat. Nos. 3,502,121, 2,083,078, and 3,710,831.